Monitoring usage of electronic equipment

ABSTRACT

The invention relates to a method for the rental of image projectors, in which a customer is provided with an image projector over an extended period. In accordance with embodiments of the invention, the image projector is arranged to sense and monitor usage during the extended period and, in at least one aspect of the invention, transmit a signal indicative of the same to a remote processing system. The remote processing system evaluates a cost corresponding to the usage and the customer is charged accordingly. The transmitted signal includes data relating to a temporal characteristic of the monitored usage within the extended period, in particular the time that the equipment was actually in use, so that the customer is only charged for the time that the image projector was actually in use.

FIELD OF THE INVENTION

This invention concerns improvements relating to electronic equipment,in particular, but not exclusively, image projectors.

BACKGROUND

Many rental companies provide a rental service involving rental of imageprojectors to commercial entities. Typically, the customer may be ahotel or conference centre which allows its clients to use the imageprojectors during meetings. The current standard system is known as “dryhire” and involves the supply of image projectors via a booking system.In the dry hire system, the rental company delivers the equipmentaccording to a booking request, and the customer is charged inaccordance with a published rate card on a full day basis or a multiplethereof. Various discounts are available depending on duration of hire.The equipment is then collected at a pre-arranged time on a pre-arrangedday by the hire company. Generally, hire of image projectors is onlypossible in blocks of one full day due to the logistics of deliveringand removing the equipment, and payment paperwork must be completed forevery transaction. Since these steps are repeated in respect of eachsuch rental activity, dry hire involves a relatively large amount ofcostly and complex communication, administration, mobilization andlogistics.

In the case of image projectors, companies who rent the equipment aretypically event facilitators (e.g. hotels and the like), who providefacilities and services to individuals or groups wishing to holdmeetings, conferences or presentations etc. Thus event facilitatorsthemselves hire out the rented equipment; as a result, an eventfacilitator is not in control of when and how the image projectors areused, instead being dependent on demand for the equipment. Theafore-mentioned problem of a lack of flexibility is thus particularlyacute when the demand for presentations and conferences fluctuates overa period of time.

It would be desirable to provide a system for the hire of imageprojectors which is less complex and more efficient in itsadministration and whereby the rental of the equipment can be made moreconvenient for a customer.

SUMMARY OF INVENTION

According to a first aspect of the present invention there is providedapparatus for monitoring usage of an image projector, the apparatuscomprising:

-   -   a usage sensor arranged to sense usage of the image projector;        and    -   a control unit adapted to monitor usage of the image projector        in response to an output from said usage sensor.

Embodiments of the invention are concerned with monitoring and recordingusage of image projectors and providing access to statistics relating tosuch usage so that a rental charge is levied which accords with anamount of usage of an image projector. It is noted that usage monitoringsystems have been proposed in the past in relation to rental of othertypes of equipment, such as rental televisions, however such systemswere not considered for use in relation to image projectors, and aregenerally unsuitable for use in relation to image projectors.

As stated in the introductory section, conventional dry hire chargingsystems are inherently inflexible, since a flat daily rate is applied,irrespective of actual use during the rental period. This arises fromthe fact that, with current image projectors on hire, no usage data ismonitored or collected to provide a more flexible charging system. Inembodiments of the invention, usage data are captured in imagegenerating equipment by at least one of various monitoring methods andtransmitted, via a transmitting component, to an administration centre.Preferably the transmitting component sends the data to theadministration centre using wireless technologies which removes the needfor fixed line connections to the image projector. Alternately, the datamay be read by a reader which is can be connected to the usagemonitoring control unit. A billing application can be run on a servercomputer, and can be made accessible via the Internet, or any otherpublicly accessible network. The billing application evaluates costsassociated with the usage of the image projector and this is madeavailable, either on request, or automatically, to a customer.

In at least one arrangement the control unit is arranged to output datarelating to a temporal characteristic of the sensed usage, such asduration of usage, and, for example, specifies a start time and an endtime of one or more periods of usage.

A usage sensor may be a software function, integrated into part of thecontrol function of the image projectors, or may be a device hardwiredinto the image projectors. Alternatively the usage sensor may be a unitthat is removably connected to the image projectors and is adapted tosense radiation emitted, for example, as a result of an image beinggenerated by the equipment.

Preferably the apparatus includes a data transmitter for transmittingthe output data either wirelessly, via SMS, GPRS and the like, or via afixed connection by means of a modem or an Ethernet link. According to afurther aspect there is provided a data processing system for processingdata relating to usage of audio-visual equipment, the data processingsystem comprising:

-   -   a data receiver arranged to receive said data indicative of        usage of audio-visual equipment;    -   accounting means arranged to evaluate a cost associated with        said usage on the basis of a predetermined charging function;        and    -   output means arranged to output the evaluated cost,    -   wherein said received data includes data relating to a temporal        characteristic of the usage of the audio-visual equipment.

The data processing system may be in the form of a software-implementedbilling application that is preferably located remote from the imageprojectors.

Thus according to the invention, billing is based on actual usage of theequipment and not to period of hire. With equipment available thatembodies these aspects of the invention, customers are far more likelyto enter into longer term contractual agreements in respect of theequipment. As a result such equipment can be kept at the customer'spremises on a long term basis, removing the need for the rental companyto collect and deliver it on a short-term basis.

In the following description the term “customer” is used to denote theparty that has entered into a contractual agreement with a rentalcompany in respect of the image projector, and may be referred to as anaccount administrator.

Further aspects of the invention are set out in the appended claims, andfeatures and advantages of the present invention will become apparentfrom the following description of preferred embodiments of theinvention, which is given by way of example only and made with referenceto the accompanying drawings.

BRIEF DESCRIPTION OF FIGURES

FIG. 1 is a schematic diagram showing an overview of an operatingenvironment within which embodiments of the invention operate;

FIG. 2 is a schematic diagram showing components of image projectorsaccording to an embodiment of the invention;

FIG. 3 a is a flow diagram showing steps carried out by the imageprojectors of FIG. 2;

FIG. 3 b is an illustrative diagram showing an example of data stored bythe image projectors shown in FIG. 2;

FIG. 4 is a flow diagram showing further steps carried out by imageprojectors of FIG. 2;

FIG. 5 is a schematic diagram showing an arrangement of a remote datareceiver and data processing system according to an embodiment of theinvention;

FIG. 6 is a flow diagram showing steps carried out by the remote datareceiver and data processing system of FIG. 5;

FIG. 7 a is a flow diagram showing further steps carried out by theremote data receiver and data processing system of FIG. 5;

FIG. 7 b is an illustrative diagram showing an example of a format ofdata output by the remote data receiver and data processing system ofFIG. 5;

FIG. 8 is a flow diagram showing further steps carried out by remotedata receiver and data processing system of FIG. 5;

FIG. 9 is a schematic diagram showing components of image projectorsaccording to a second embodiment of the invention;

FIG. 10 is a circuit diagram illustrating components of a monitoringunit in accordance with a further embodiment of the invention; and

FIG. 11 is a circuit diagram illustrating components of a readout unitin accordance with the further embodiment of the invention.

DETAILED DESCRIPTION OF DRAWINGS

Embodiments of the invention will now be described in more detail. Afirst embodiment will be described with reference to FIGS. 1 to 8.

Referring to FIG. 1, at a system level, the communications environmentwithin which embodiments of the invention can operate comprises acellular network comprising a base station 13, and a GPRS (GeneralPacket Radio Services) network including a Gateway GPRS Support Node(GGSN) 15 The GGSN 15 is a network element that provides an interfacebetween the GPRS network and external data networks, such as theInternet N1 or private networks. The GGNS 15 receives data packets frommobile devices, and forwards them, in a known manner, through theInternet N1 or private networks.

The Internet N1 is connected to an administration centre, which in oneembodiment of the invention houses several computer terminals including:a web server S1; an application server S2, on which a billingapplication according to the invention is stored; a user terminal T2,which is arranged to access, locally, the web server S1; and a printerT3, which can be used to print data viewed by the user at terminal T2.The configuration of servers S1, S2 shown in FIG. 1 is merelyillustrative of one server arrangement; the skilled person would realisefor example that the functionality provided by the web server and theapplication server could be combined on a single terminal.

Terminal T1 is a remote terminal that can communicate with web server S1in order to access applications running on the application server.Remote terminal T1 is arranged to access web server S1 via a link L1,which is facilitated through one of the known hardware connectionmethods e.g. modem, ISDN, LAN and supports a request protocol such ashypertext transfer protocol (HTTP). The remote terminal T1 is arrangedto run a browser that receives data from the web server S1 (e.g. via theHypertext Markup Language (HTML) or the eXtensible Markup Language(XML), or any variants thereof), to interpret the received data and todisplay the same on the browser for viewing by the user. In the eventthat the functionality provided by the web server and application serveris combined as a single server application running on a single machine,the remote terminal T1 could be arranged to run a bespoke clientapplication that is configured to co-operate with the combined serverapplication.

Typically a customer will access the billing application via a remoteterminal such as T1 while an account administrator will access theapplication via the local terminal T2.

Referring to FIG. 2, in this embodiment a video image projector 10comprises: an on/off button 200; a control unit 201 for controllingoperation of the device 10; a lamp 203 providing a display illuminationsource; a light modulator 205 for modulating the light from the source.The device 10 is arranged to receive data signals from, for example, alaptop computer 215 via display data input 207. The modulator 207 iscontrolled in accordance with display data input 207 or internal displaydata; an output lens 209; and a transmission unit TU. These signals areprocessed in a known manner by the control unit 201 and projected viathe lamp 203, modulator 205 and output lens 209 onto a projector screen211.

The device 10 can operate in one of two modes whilst a power supply (notshown) is connected: a standby mode, in which the control unit 201 isactive but the lamp 203 is normally switched off, and in a display mode,in which the control unit is active but the lamp 203 is switched on.After a period of non-use, or if a blank signal is received via input207, the device will automatically enter standby mode, in which the lampis powered off. If a control element, such as the on-off button, is thenagain actuated, or if an image data signal is received via input 207,the device comes out of standby mode and switches the lamp 203 on onceagain. In accordance with embodiments of the invention, a usage count isincremented when the device is in active mode (when an image is beingprojected), and not standby mode (when no image is being projected).

In addition to the conventional programs constituting the control unit201, the control unit 201 comprises a computer program, or a suite ofcomputer programs, arranged to monitor the utility status of imageprojector 10 and to store data indicative of the amount of time that thelamp is powered on in a local non-volatile memory 213. In use, andreferring to FIG. 3 a, the control unit 201 monitors the status of thelamp 203 (step 301), and, when the lamp is identified to have beenpowered on, the control unit records (step 303), in local memory 213,the date and time corresponding to the instant at which the lamp waspowered on. The control unit then reverts (step 305) to monitoring thestatus of the lamp 203, so as to identify when the lamp is powered off.When the lamp is identified to have been powered off, the control unit201 records (step 307) the date and time, again by storing this data inthe local memory 213. An example of the format of data in the localmemory 213 is shown in FIG. 3 b.

In one arrangement, the control unit 201 is arranged to transmit storedusage data to the administration centre, via the transmission unit TU,when certain specified conditions have been satisfied. These conditionsmay be based on elapsed time intervals and/or trends in usage data, andare described in more detail below with reference to FIG. 4. Since, inthe present embodiment, data are transmitted using the GPRScommunication service, the control unit 201 includes packetising meansfor packetising the usage data stored in the local memory 213; in theevent that the administration centre wishes to verify the source ofpackets purporting to emanate from image projectors 10 leased by theadministration centre, the control unit 201 of such image projectors 10may also include means for encrypting the packetised data. In any event,the packets include data identifying the image projector 10 associatedtherewith.

In addition, the control unit 201 may be arranged to display usage data,either at time of transmission, periodically (in accordance with aspecified time period), or in accordance with an explicit request (via aset of selectable menu options), on the projector screen 211.

The transmission of data to the administration centre will now bedescribed, with reference to FIG. 4. At step 401, the control unit 201checks whether the transmission conditions have been satisfied, namelythat both/either a specified time has elapsed and/or that the usage datahas changed since data was last sent. If these conditions have beensatisfied, the control unit 201 retrieves data from the memory 213,packetises the same (step 403), and proceeds to forward the packets tothe transmission unit. Once the control unit 201 has forwarded thepackets to the transmission unit, it may empty the local cache 213 (step404).

Referring to FIG. 5, the transmission unit TU then transmits the datapackets (step 405), which are received by the base station 13 andforwarded, in a known manner, to the remote input 501 (which may be adata server) of the administration centre. Data received at the remoteinput 501 is forwarded to a billing application 503 running on, forexample, an application server located within the administration centre.

The billing application will now be described with reference to FIG. 5,which is a schematic block diagram showing flow of data between the GGSN15 and the administration centre. As stated above with reference to FIG.1, the billing application 503 runs on application server S2, and isarranged to receive signals from the remote input 501 and tointer-operate with web server S1 and database DB1. The billingapplication 503 comprises a computer program, or a suite of computerprograms, arranged to receive usage data from the image projector 10 andto covert the usage data into corresponding cost data and store the costdata in a database DB1. Each image projector customer has a databaserecord associated therewith, which stores customer ID, authenticationdetails, usage and corresponding cost data.

The billing application 503 is also operable to receive requests toaccess the cost data from a remote terminal T1, and may include anauthentication routine for authenticating access to the billingapplication 503. Such requests may be input via a graphical userinterface, such as a browser, which runs on the remote terminal T1 andis arranged to send and receive input data to/from web server S1.

In the event that a customer wants to view his most recent usage andcost data, the billing application is arranged to transmit a request forusage data to the control unit 201 of the image projector 10; referringback to FIG. 4, this causes the control unit 201 to step through steps405, 404 and 405 described above.

Alternatively, a customer may prefer to automatically receive periodiccost updates. Accordingly, the billing application 503 may have accessto a plurality of template profiles P1, P2, each of which specifies anupdate frequency and a preferred mode of notification and which can beselected by a customer via the browser running on his remote terminalT1. For example, a first such profile P1 could specify an updatefrequency of monthly and a preferred notification mode of SMS, while asecond such profile P2 could specify an update frequency of quarterly,and a preferred notification mode of email. The notification frequencyand transmission details (SMS and email data) can be input when acustomer is selecting a profile, and stored in the database recordcorresponding to this customer ID.

In order to relay email messages, the billing application 503 has to becapable of sending and receiving SMTP (Simple Mail Transfer Protocol)messages; this can be provided by a software component (not shown)arranged to establish two-way transmission channels to a receiver-SMTP,as is described in Request For Comments (RFC) 821, available from theIETF and at the following uniform resource locator (URL) at May 2003:http://www.ietf.org/rfc/rfc0821.txt.

FIG. 6 shows the steps performed by the billing application 503 when itreceives usage data at the remote input 501. At step 601, data packetsare passed to the billing application 503, which, at step 603,identifies the customer to which the data corresponds. Step 603 involvesunencapsulating (and if necessary unencrypting) the packets so as toidentify the image projector 10 associated with the received packets.Assuming that the received data relates to a registered customer and issuccessfully unencrypted, the billing application 503 proceeds toconvert (step 605) the usage data into a cost. In one arrangement, thecustomer could be charged for the total usage time in accordance with afixed hourly rate (FhR) as follows:Charge=TuT×FhR.

Alternatively, the customer may be charged in accordance with a scale ofcharges, for example having an hourly rate which decreases withincreased usage time, or any other charging function based on themonitored usage time that the equipment has actually been in use. Havingconverted the usage data into cost, this is stored (step 607) in thedatabase DB1 in whichever record corresponds to the identified customer.The cost data are then available for access by, or transmission to, thecustomer.

Access to the stored cost data will now be described with referencefirstly to FIGS. 7 a and 7 b, which show steps involved in receiving andprocessing an explicit request for cost data, and secondly withreference to FIG. 8, which shows steps involved in automatically sendingcost data to a customer in accordance with his previously definedprofile.

Referring to FIG. 7 a, a customer enters an appropriate URL in a browserrunning on his terminal T1, which causes the web server S1 to serve webpages to the customer's browser, requesting user name and password (step701). Once the customer has entered his identification details, the webserver S1 passes the entered details to the billing application 503 inorder to authenticate the customer's request (step 703). Assuming thatthe customer's request is successfully authenticated, the billingapplication 503 forms a query (e.g. using SQL (Standard Query Language))to retrieve data from database DB1 corresponding to the customer, andsends the query to the database DB1 (step 705), which retrieves anddownloads the data to the billing application (step 707). Thereafter thebilling application 503 transmits the cost data, via the web server S1,to the browser, which displays the same (step 709). In one arrangement,the HTML (or XML) tags within which the cost data are encapsulated causethe browser to display an invoice such as that shown in FIG. 7 b.

This invoice is essentially an itemized bill showing individual usageevents (date, time on, time off 71, 73, 75) relating to an imageprojector rental account. When an image projector is leased to a hotel,it may be expected that the hotel itself “hires” the device to severaldifferent companies (e.g. for conferences, presentations etc.), and maywish to bill these companies in respect of their individual usage.Accordingly, an account manager for the device, logging onto the billingapplication 503 via remote terminal T1, can submit a query for cost datain respect of a specific period (e.g. corresponding to day 1 whencompany 1 was using the device). The invoice returned at step 709 willthen relate to that period only. Alternatively the account manager couldsubmit a plurality of queries, each specifying a respective period, sothat the data returned at step 709 will comprise a correspondingplurality of individual invoices, each corresponding to its respectiveperiod.

Turning now to FIG. 8, in the event that the customer has registeredwith the billing application 503 as requiring notification of his costdata via automatic cost updates—e.g. via one of the profiles P1 . . . Pndescribed above—the processing program invokes a system timer inaccordance with the update frequency specified by the customer. When thetimer has expired, step 801, the processing billing application 503forms a query (e.g. using SQL (Standard Query Language)) to retrievedata from database DB1 corresponding to the customer, and sends thequery to the database DB1 (step 803), which retrieves and downloads thedata to the billing application 513 (step 805). At the same time, orshortly thereafter, the billing application 503 retrieves details of thecustomer's preferred transmission mode and transmission data (such asdestination numbers and addresses etc.) (step 807) and transmits thedownloaded data in accordance with that data (step 809). For example, inthe event that the customer has specified SMS as his preferred mode ofdelivery, step 809 involves the billing application 503 encapsulatingthe cost data received at step 805 into an SMS in accordance with thecustomer details received at step 807.

In the event that the customer has specified email as his preferred modeof delivery, the billing application 503 passes the cost data andspecified email address (retrieved at step 807) to the SMTP softwarecomponent, so that step 809 involves inserting the cost data into eitherthe subject or the body of an email message and sending the email to thespecified email address in accordance with the SMTP protocol.

A customer may specify GPRS as his preferred mode of delivery, settingthe destination address to that of the image projector 10. Accordingly,when such packets are received by the image projector 10, the controlunit 201 can be arranged to display the received data on projectorscreen 211.

Although the processes have been described with reference to sendingcost data as SMS, email and IP data packets, it will be appreciated thatthese are merely illustrative of possible transmission modes, and thatother modes are possible. These include (but are not limited to) pagingand recorded voice messages (via DTMF).

As stated above with reference to FIG. 1, an administrator working atlocal terminal T2 can access the billing application 503 via the webserver S1, for example to print off invoices on printer T3. Theseinvoices may then be posted to customers. In addition to storing cost,or debit due, in respect of an image projector, the database DB1 canalso be arranged to store credit, or payments made, in respect of theimage projector. This data could be accessed by the administrator atlocal terminal T2 as part of account management procedures. In the eventthat payment has not been received in respect of an image projector, thebilling application (preferably under control of the administrator) hasthe facility to transmit a control signal to the image projector,causing the device to be disabled until such time as suitable paymenthas been made.

In the above-described embodiment, the image projector 10 includes thetransmission unit TU therein. However, the transmission unit TU could belocated in a separate device, such as a portable laptop, which isarranged to connect to the image projector via, e.g. either a bespokeport or an existing (e.g. RS232) port in the image projector, andreceive the usage data directly from the control unit 201. Thus in suchan arrangement, the laptop transmits the usage data to the billingapplication 503.

In the above-described embodiment, it is assumed that the imageprojector 10 is configured to include an in-built usage monitoringsystem—in the above description the control unit 201 is described asbeing arranged to record usage of the image projector 10. However, theinvention can also be applied to image projectors that are not soconfigured; in such cases (an) additional device(s) are required toexternally monitor usage of the image projector.

An example of such an additional device, referred to as a monitoringunit, will now be described.

Referring to FIG. 9, the monitoring unit may, for example, be mounted inthe lamp cavity of the image projector 10, and include a radiationsensor 912 in the form of a cadmium sulphide (CdS) cell mounted in theunit to detect radiation impinging thereon. The cell 912 is connected tomicroprocessor controller 914, which uses an external oscillator 916,running at 100 KHz, selected to reduce power consumption of thecontroller 914 whilst providing sufficiently accurate timing cycles. Theoscillator 916 is typically accurate to within 1% and more preferably towithin 0.1%. The monitoring unit includes an internal battery 918, andthe sensor cell 912 is mounted so as to detect radiation emitted duringuse of the equipment in which the monitoring unit is housed, and in alocation in which the amount of ambient light impinging on the cell whenthe device is not in use is insufficient to trigger monitoring by thecontroller 914.

When the lamp is switched on, radiation impinging on the sensor 912causes the resistance of the cell 912 to fall from in the region of 10Mohm to around 50 Kohm. Referring to FIG. 10, this fall in resistancecauses an input to logic gate 1010 to switch from low to high, and theoutput from logic gate 1010 is latched in a flip flop latch formed bylogic gates 1012 and 1014. The output of sensor output line 1016—fromlow to high—is sensed by the controller 914, in response to which thecontroller 914 switches from a relatively low power “sleep” mode to arelatively high power monitoring mode, in which an elapsed time periodis monitored. Whilst the output on sensor output line 1016 remains high,a cumulative time period monitored by the controller 914 is incrementedusing the timing pulses received from oscillator 916. The controller 914is adapted to monitor elapsed time in preset time periods, for example 1minute time intervals. At the end of each interval, an attempt is madeby the controller 914 to reset the latch previously set by the radiationcell activation. If the lamp 203 is still on the latch cannot be reset,and the output on the sensor output line 1016 remains high. If, on theother hand, the lamp 203 is off, the latch is reset and the controller914 switches back to a low-power “sleep” mode, during which the elapsedtime period is no longer monitored. Thus, the controller 914 graduallybuilds up a cumulative count of time unit intervals which correspond tothe amount of time during which the lamp of the device is switched on,that is to say the monitoring unit monitors usage of the imageprojectors in terms of periods during which the lamp is switched on.When the device is in standby mode, and the lamp is off, the equipmentis taken not to be in use and therefore no usage is registered duringusage of the device in a standby state, even though the device may beotherwise powered up.

When the controller 914 is in a “sleep” mode, the oscillation of theoscillator 916 is halted, thereby further reducing power consumption. Inthis “sleep” mode, the current within the monitoring unit falls to lessthan 1 μA. On the other hand, during active timing, the count within themonitoring unit is typically 50 μA. The device is typically capable ofmonitoring active usage of the device, corresponding to periods when thelamp is switched on, of up to 5000 hours in total.

In addition to the above-described monitoring functions, the monitoringunit can include a transmission unit TU of the type described inaccordance with the first embodiment of the invention (and variantsthereon), and which may, for example, be powered by battery 918.Referring back to FIG. 9, the controller 914 is arranged to store theaccumulated time, and, at specified intervals, transmit the data, viathe transmission unit TU, to the billing application 503.

Alternatively, the monitoring unit can include components for directlyreading out data from the controller 914, in which case the transmissionunit TU can conveniently be arranged in operative association with adevice (referred to below as a readout unit) arranged to perform such areadout operation. The readout can, for example, be carried out byinserting a jack into a bespoke socket in the monitoring unit (notshown), which connects at contacts 1018, 1020 in the socket, causing ajack sensor line 1022 to switch between a high signal state and a lowsignal state, which is detected by the controller 914. In response todetection of insertion of a jack, the controller 914 switches between alow-power “sleep” mode and a high-power data readout mode. In the datareadout mode, the controller 914 intermittently sends the current timerreading, for example in RS232 format, in a data signal sent out via dataline 1026, which connects to the jack via electrical contact 1024.

An example of the electrical components forming such a readout unit isshown in FIG. 11. These components include an external oscillatorcrystal 1044, which runs at a selected cycle rate, for example 100 KHz,ensuring a relatively low-power operation of the readout unit; and ajack 1046 which, when inserted in a corresponding socket in themonitoring unit, interconnects contacts 1018 and 1020 and connects adata line 1048 to the readout electrical contact 1024 in the monitoringunit. The readout unit also includes a battery 1050 which is used topower the electrical components, and a power control circuit whichswitches the power supply circuit within the readout unit on in responseto the sensing of data on data line 1048. The readout unit power isswitched on via a gate 1052 and a regulator 1054. On receipt of data viathe data line 1048, the data are level shifted by a gate 1056 andreceived by a readout control unit 1042. The control unit 1042 processesthe received data and formats it for transmission by the transmissionunit TU. Alternatively or additionally, the control unit 1042 mayprocess the data into a format suitable for display; the readout unitmay, for example, include an LCD display 1040, which shows the storedusage in terms of hours and minutes. This latter arrangement isparticularly beneficial in cases where rental companies manuallyretrieve usage data (by means of such a readout unit): when the rentalcompany hands over the device 10 to a customer of the rental company, areading of the current usage can be taken by plugging the jack 1046 intothe relevant socket on the device 10, and thereafter at predeterminedintervals either the customer or the rental company can repeatperforming the usage readings.

In the event that the customer is a hotel or conference organizer, andhas rented a plurality of such devices 10, a single readout unit ispreferably designed to cooperate with each of the plurality.

It is to be understood that the monitoring and readout units—as a“retro-fit” unit to a standard display device—are, in their own right,another aspect of the present invention. In other words the monitoringand readout units can operate independently of (i.e. function forpurposes other than) the transmission of usage data described above.

It should be noted that all aspects of the invention are not limited tovideo image projectors. The invention extends to other audio-visualequipment including:

-   -   still image projector equipment including overhead projectors        and slide projectors;    -   video displays and monitors, including plasma display screens,        cathode ray tube (CRT) screens, liquid crystal display (LCD)        screens;    -   computer equipment (laptop, desktop, server etc.); and    -   video recording and reproducing equipment including video        cameras and video storage devices.

It is to be understood that the control units of these devices will beconfigured to monitor an attribute which indicates actual usage of thedevice in order to generate the monitored usage data, and the remainderof the data processing and billing system described above will be usedin combination with such control units.

With particular reference to the retro-fit aspect of the invention,where a monitoring unit is installed in the lamp compartment of a devicehaving a lamp which is energized during use, in an alternativeembodiment a monitoring unit may be installed in a different type ofelectronic device. For example, the unit may be installed in a rentalportable computer of the type having a screen hingedly attached to abase portion. In this case, the computer has areas, namely by thesurfaces which face one and other on the screen and base portion, whichare exposed to ambient radiation when in an opened configuration whenthe device is in use, and which are less exposed to ambient radiationwhen in a closed configuration when the device is not in use. Themonitoring unit may then be installed such that the sensor is located soas to sense ambient radiation when the computer is opened, thusproviding a mechanism whereby a signal indicating actual use of thecomputer may be monitored. A similar arrangement may be used on otherdevices, in which an opening mechanism is provided, the openingmechanism exposing an area to ambient radiation.

Furthermore, in relation to the second aspect of the invention, thesensor is described as detecting visible radiation emitted by the lamp.This thus uses a reliable characteristic signal indicating the equipmentto be in use. In an alternative embodiment, heat radiation from thedevice may be detected in the form for example of a temperaturereading—in this case the monitoring unit may for example be mounted tothe outside of the device housing. In this case, use of the equipment istaken to occur when a heat reading above a predetermined threshold isreached. However, it has been found, in particular in devices which usecooling fans during operation, that it can be difficult to distinguishoperation in standby mode, with the fan switched off for whichpreferably no charge is incurred, and fully operative mode with the fanswitched on. Hence, locating the monitoring unit inside the lamp housingto detect radiation emitted from the lamp is preferred.

Whilst in the above embodiment the transmission unit TU is configured soas to send usage data as GPRS packets, as an alternative, or inaddition, the transmission unit could be configured to send and receivedata in accordance with Wireless LAN (WLAN) or Bluetooth protocols.These are short range communication mechanisms, and data can only besent in accordance therewith when a base station is located sufficientlyclose to the image projector. For further information relating toimplementation of the WLAN standard 802.11, the reader is referred tohttp://grouper.ieee.org/groups/802/11/, from where a copy of the 802.11standard can be downloaded. In addition, the user is referred to:“802.11 Wireless Networks: The Definitive Guide to Creating andAdministering Wireless Networks” by Matthew Gast, published by O-Reillyin April 2002 (ISBN 0-596-00183-5). For further information relating toimplementation of the Bluetooth standard, the reader is referred to“Bluetooth Revealed” by Brent A Miller, published by Prentice Hall inSeptember 2000 (ISBN 0-13-090294-2).

Alternatively, the control unit 201 could transmit the usage data in theform of Short Message Service (SMS) messages instead of, or in additionto, writing to the local memory 213.

As yet a further alternative, the image projector 10 could connectdirectly to a local area network (LAN), or via a modem to a publicswitched telephone network (PSTN), and transmit the usage data to theadministration centre accordingly.

In relation to the second aspect of the invention, the transmitting unitTU could be embodied in a portable laptop device that connects to themonitoring unit, rather than in the bespoke readout unit.

It is to be understood that any feature described in relation to oneembodiment may also be used in other of the embodiments. Furthermore,equivalents and modifications not described above may also be employedwithout departing from the scope of the invention, which is defined inthe accompanying claims.

1. Apparatus for monitoring usage of an image projector, said apparatuscomprising: a usage sensor arranged to sense usage of the imageprojector; and a control unit adapted to monitor usage of the imageprojector in response to an output from said sensor.
 2. Apparatusaccording to claim 1, wherein the control unit is adapted to monitor anelapsed time in which the projector is in use.
 3. Apparatus according toclaim 1, including a data transmitter for transmitting data indicativeof said sensed usage.
 4. Apparatus according to claim 3, wherein thedata transmitter comprises a wireless radio transmitter.
 5. Apparatusaccording to claim 3, wherein the data transmitter is arranged separatefrom said image projector.
 6. Apparatus according to claim 3, whereinthe data transmitter is adapted to transmit data relating to a temporalcharacteristic of the sensed usage.
 7. Apparatus according to claim 6,wherein said temporal data includes data indicative of duration of oneor more sensed periods of usage.
 8. Apparatus according to claim 6,wherein said temporal data includes data indicative of a start time andan end time of a sensed period of usage.
 9. Apparatus according to claim1, in which the apparatus is arranged to initiate transmission of sensedusage data in response to conditions satisfying one or morepredetermined criteria.
 10. Apparatus according to claim 1, wherein theusage sensor is integral to the image projector.
 11. Apparatus accordingto claim 1, wherein the usage sensor is removably connectable to theimage projector.
 12. Apparatus according to claim 1, including a datareceiver arranged to receive remotely generated control signals for usein controlling operation of the image projector.
 13. Apparatus accordingto claim 12, wherein the apparatus is arranged to disable operation ofthe image projector in response to receipt of a disabling controlsignal.
 14. Apparatus according to claim 12, wherein the data receiveris arranged to receive a remotely generated request for usage data andthe apparatus is arranged, in response thereto, to retrieve stored usagedata for transmission.
 15. Apparatus according to claim 1, wherein theusage sensor is adapted to sense radiation which is emitted as a resultof an image being generated by the projector.
 16. Apparatus according toclaim 1, wherein the usage sensor is adapted to sense radiation emittedfrom a lamp in the projector.
 17. Apparatus according to claim 1,wherein the usage sensor is adapted to sense heat radiation. 18.Apparatus according to claim 1, wherein the usage sensor is in the formof a cadmium sulphide (CdS) sensor.
 19. Apparatus according to claim 1,further comprising a display unit which is adapted to receive data fromsaid control unit and to display a usage reading based on the usagemonitored by the control unit.
 20. Apparatus according to claim 19,wherein the display unit is removably connectable to the control unit.21. Apparatus according to claim 20, wherein the display unit has apower control circuit providing a low power mode and a high power mode,and wherein the control circuit is adapted to switch the display unitbetween the low power mode and the high power mode in response toconnection of the control unit thereto.
 22. A data processing system forprocessing data relating to usage of audio-visual equipment, the dataprocessing system comprising: a data receiver arranged to receive saiddata indicative of usage of audiovisual equipment; accounting meansarranged to evaluate a cost associated with said usage on the basis of apredetermined charging function; and output means arranged to output theevaluated cost, wherein said received data includes data relating to atemporal characteristic of the usage of the audio-visual equipment. 23.A data processing system according to claim 22, wherein the systemincludes receiving means arranged to receive a request for cost datarelating to said usage, wherein the output means is arranged to outputthe evaluated cost data in response to receipt of said request.
 24. Adata processing system according to claim 23, wherein the requestcomprises an automatically generated request.
 25. A data processingsystem according to claim 23, wherein the request includes data defininga time period in respect of which cost data are required.
 26. A dataprocessing system according to claim 22, wherein the output medium isany one of SMS, GPRS, TCP/IP.
 27. A data processing system according toclaim 22, including control signal generating means arranged to generatea control signal for controlling image projectors, wherein the system isarranged to output the generated control signal to the audio-visualequipment.
 28. A data processing system according to claim 27, whereinthe control signal generating means is arranged to generate a saidcontrol signal in response to conditions satisfying one or morepredetermined criteria.
 29. A data processing system according to claim27, wherein the control signal comprises a signal arranged to disablethe audio-visual equipment.
 30. A method of monitoring usage of an imageprojector, including: sensing usage of the image projector; transmittingdata indicative of said sensed usage to a processing system; andprocessing the sensed usage data on the basis of a predetermined costcriterion so as to identify a cost associated therewith; in which saidtransmitted data includes data relating to a temporal characteristic ofthe monitored usage.
 31. A method according to claim 30, furtherincluding receiving a request for cost data relating to specified animage projector; accessing the processed cost in respect of thespecified an image projector; and outputting the same.
 32. A methodaccording to claim 30, in which usage of the image projector relates tousage thereof by a customer, the method including monitoring payment bythe customer in respect of said usage.
 33. A method according to claim32, including evaluating said monitored payment in accordance with apredetermined payment criterion and transmitting a control signal to theimage projector in dependence on the evaluation.
 34. A method for therental of electronic equipment, in which a customer is provided withelectronic equipment over an extended period, and the image projector isprovided with a usage monitoring system adapted to monitor usage of theimage projector, whereby a signal indicating actual usage of theequipment during the extended period is monitored, and the customer ischarged in accordance with a temporal characteristic of the monitoredsignal.
 35. A method according to claim 34, including transmitting themonitored signal to a remote processing system, and charging thecustomer in accordance with the monitored usage.
 36. A method accordingto claim 34, in which monitoring usage of the image projector comprisesmonitoring radiation emitted during usage thereof.
 37. Apparatus formonitoring usage of audio-visual equipment, said apparatus comprising: ausage sensor arranged to sense usage of the audio-visual equipment; anda control unit adapted to monitor usage of the audio-visual equipment inresponse to an output from said sensor.
 38. Apparatus according to claim37, in which the audio-visual equipment comprises a device having anarea which is exposed to ambient radiation when in a configuration inwhich the device is in use, and which is less exposed to ambientradiation when in a configuration in which the device is not in use, andwherein the sensor is located to sense said ambient radiation in saidarea.
 39. Apparatus according to claim 38, wherein the audio-visualequipment comprises an opening mechanism which exposes said area toambient radiation.
 40. Apparatus according to claim 39, wherein thedevice is a portable computer having a screen hingedly attached to abase portion.